<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>11_tab</title>
    <style>
        ul li {
            list-style: none;
            display: inline-block;
            border: 0px;
            margin: 0px;
            background-color: aquamarine;
        }

        div {
            background-color: bluesky;
            ;
        }
    </style>
</head>

<body>
    <ul id="tab">
        <li id="tab1">tab1</li>
        <li id="tab2">tab2</li>
        <li id="tab3">tab3</li>
    </ul>
    <div class="container">
        <div class="content1">aaaaaaaaaaaaaaaaaaa</div>
        <div class="content2" style="display: none">bbbbbbbbbbb</div>
        <div class="content3" style="display: none">cccccccccc</div>
    </div>
</body>

</html>